Everyone interested in visiting Boom Chicago can take a look at the following link: groupon.nl/deals/…91863
This website has daily deals and their current online offer is an admission ticket to Boom Chicago for 10 euros instead of 20 euros. (I haven't been to a show myself, but it seems to be quite popular among tourists)
You can use the voucher only on Sundays-Thursdays between 30th September 2010 - 31 March 2011. The following shows are available: Boom Chicago: "Your Worst Fears", "There is No Such Thing as Sinterklaas", "Boom Chicago’s Very Big Holiday Show" and a new show that will be announced shortly.
Also, be sure to make a reservation in advance, either by email or phone.
You might have to sign up for Groupon before ordering the tickets, but it's worth the effort.
If you're interested, be quick, because the offer expires after 24 hours.